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Half failed LEDs

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raymondj(at)frontiernet.n
Guest

Posted: Mon Apr 21, 2014 4:11 am Post subject: Half failed LEDs

I just removed about 8 blue LEDs from a string of lights that no longer 

emitted light, but still have continuity.  If any one wants them to 

investigate, I'll mail them out.

-- 

Raymond Julian

Kettle River, MN



The things we admire in men, kindness and generosity, openness, honesty, 

understanding and feeling are the concomitants of failure in our system. 

And those traits we detest, sharpness, greed, acquisitiveness, meanness, 

egotism and self-interest are the traits of success. And while men 

admire the quality of the first they love the produce of the second. 

-John Steinbeck, novelist, Nobel laureate (1902-1968)

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nuckolls.bob(at)aeroelect
Guest

Posted: Tue Apr 22, 2014 5:19 am Post subject: Half failed LEDs

At 07:09 AM 4/21/2014, you wrote:

 	  Quote: 	
		  



I just removed about 8 blue LEDs from a string of lights that no 

longer emitted light, but still have continuity.  If any one wants 

them to investigate, I'll mail them out.


	


   When you measure them with an ohmmeter, do they

   show the same or similar resistance for either

   polarity of the test leads?



   Bob . . .

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raymondj(at)frontiernet.n
Guest

Posted: Tue Apr 22, 2014 7:35 am Post subject: Half failed LEDs

Most of them were in the 4-8k range both ways.  A couple were in the 90k 

range both ways, and one was about 90k one way and about 150k the other.

They were in series with other LEDs  and all carried enough current to 

allow the other LEDs to continue to light.

Raymond Julian

Kettle River, MN

The things we admire in men, kindness and generosity, openness, honesty, 

understanding and feeling are the concomitants of failure in our system. 

And those traits we detest, sharpness, greed, acquisitiveness, meanness, 

egotism and self-interest are the traits of success. And while men 

admire the quality of the first they love the produce of the second. 

-John Steinbeck, novelist, Nobel laureate (1902-1968)

On 04/22/2014 08:18 AM, Robert L. Nuckolls, III wrote:

 	  Quote: 	

 <nuckolls.bob(at)aeroelectric.com>

 At 07:09 AM 4/21/2014, you wrote:

> 

>

> I just removed about 8 blue LEDs from a string of lights that no

> longer emitted light, but still have continuity.  If any one wants

> them to investigate, I'll mail them out.

    When you measure them with an ohmmeter, do they

    show the same or similar resistance for either

    polarity of the test leads?

    Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Tue Apr 22, 2014 2:03 pm Post subject: Half failed LEDs

At 10:31 AM 4/22/2014, you wrote:

 	  Quote: 	
		  



Most of them were in the 4-8k range both ways.  A couple were in the 

90k range both ways, and one was about 90k one way and about 150k the other.

They were in series with other LEDs  and all carried enough current 

to allow the other LEDs to continue to light.


	


   Interesting. I'm not familiar with the failure modes

   in LEDs . . . so getting first hand look at the

   parts would probably not be useful. The fact that

   your readings were so high but with conductivity in

   both directions suggests that there's some degree

   of P/N junction activity going on . . . in other

   words, I suspect they failed in some low energy

   event as opposed to high energy that tends to fuse

   things into more solid pieces of material.



   Bob . . .

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raymondj(at)frontiernet.n
Guest

Posted: Tue Apr 22, 2014 2:47 pm Post subject: Half failed LEDs

They just weren't lit one day when I looked at them.  They were on 24/7. 

  I'll just recycle them, unless someone else wants them.



Raymond Julian

Kettle River, MN



The things we admire in men, kindness and generosity, openness, honesty, 

understanding and feeling are the concomitants of failure in our system. 

And those traits we detest, sharpness, greed, acquisitiveness, meanness, 

egotism and self-interest are the traits of success. And while men 

admire the quality of the first they love the produce of the second. 

-John Steinbeck, novelist, Nobel laureate (1902-1968)



On 04/22/2014 04:59 PM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   

 <nuckolls.bob(at)aeroelectric.com>



 At 10:31 AM 4/22/2014, you wrote:

> 

>

> Most of them were in the 4-8k range both ways.  A couple were in the

> 90k range both ways, and one was about 90k one way and about 150k the

> other.

> They were in series with other LEDs  and all carried enough current to

> allow the other LEDs to continue to light.



    Interesting. I'm not familiar with the failure modes

    in LEDs . . . so getting first hand look at the

    parts would probably not be useful. The fact that

    your readings were so high but with conductivity in

    both directions suggests that there's some degree

    of P/N junction activity going on . . . in other

    words, I suspect they failed in some low energy

    event as opposed to high energy that tends to fuse

    things into more solid pieces of material.



    Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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